A reconciliation of the beginning and ending balance of unrecognized tax benefits is as follows:
| (dollars in millions) | ||||||||||||
| 2013 | 2012 | 2011 | ||||||||||
|
Balance at January 1, |
$ | 2,943 | $ | 3,078 | $ | 3,242 | ||||||
|
Additions based on tax positions related to the current year |
116 | 131 | 111 | |||||||||
|
Additions for tax positions of prior years |
250 | 92 | 456 | |||||||||
|
Reductions for tax positions of prior years |
(801 | ) | (415 | ) | (644 | ) | ||||||
|
Settlements |
(210 | ) | 100 | (56 | ) | |||||||
|
Lapses of statutes of limitations |
(168 | ) | (43 | ) | (31 | ) | ||||||
|
|
|
|||||||||||
|
Balance at December 31, |
$ | 2,130 | $ | 2,943 | $ | 3,078 | ||||||
|
|
|
|||||||||||